The present invention relates to improvements in plastic reclosable fasteners with sliders for opening and closing the reclosable fasteners on plastic bags and the like and particularly to a plastic reclosable fastener with self-locking slider.
Plastic zippers with sliders are well known in the art. The plastic zippers have profiles and include a pair of male and female fastener elements in the form of reclosable interlocking rib and groove elements with a slider for opening and closing the rib and groove elements. In the manufacture of thermoplastic film bags, a pair of these male and female fastener elements extend along the mouth of the bags and these male and female elements are adapted to be secured in any suitable manner to the flexible walls of the thermoplastic film bag. These elements may be integral marginal portions of such walls or they may be extruded separately and thereafter attached to the walls along the mouth of the bag. A method of continuously providing such a fastener on the thermoplastic film is disclosed in U.S. Pat. No. 3,462,332. The U.S. Pat. No. 3,259,951 discloses an example of a thermoplastic bag where the fastener elements are extruded separately and thereafter attached to the walls along the mouth of the bag. This patent also discloses a slider and flexible closure strips adapted to be joined by such slider to form an air tight closure.
The sliders for opening or closing the reclosable fasteners are adapted to be assembled with the fastener or zipper by an endwise assembly or by a relative transverse maneuver An example of a fastener with an endwise assembly of the slider is disclosed in the aforesaid U.S. Pat. No. 3,259,951. In some instances the sliders are formed of multiple parts and assembled on the zipper. The assembly may be simplified if the slider is formed of one part and the sides are foldable into position when assembled on the zipper. Examples of foldable plastic sliders are disclosed in the related applications referred to below.